Abstract: A modular connector element has a hook, a catch, and fittings for connection to an end of a hollow log for assembly into a wall or building superstructure. In assembling three such connector elements in a sequence conforming a corner between two structural walls, the hook of the middle connector element makes a click connection with a catch formed on a second such connector element positioned on one side of the middle connector element, and the catch of the middle connector element makes a click connection with a hook formed on a third such connector element positioned on the side of the middle connector element opposite the second connector element. The connector elements with their respective logs are thus rapidly, securely and manually click-locked together to erect walls and building superstructures.